diff --git a/hnn_core/tests/test_viz.py b/hnn_core/tests/test_viz.py
index 0a5057e0f..4b324217f 100644
--- a/hnn_core/tests/test_viz.py
+++ b/hnn_core/tests/test_viz.py
@@ -248,7 +248,7 @@ def test_dipole_visualization(setup_net):
 
 
 class TestCellResponsePlotters:
-
+    """Tests plotting methods of the CellResponse class"""
     @pytest.fixture(scope='class')
     def class_setup_net(self):
         hnn_core_root = op.dirname(hnn_core.__file__)
@@ -302,31 +302,33 @@ def test_spikes_raster_colors(self, base_simulation_spikes):
         def _get_line_hex_colors(fig):
             colors = [matplotlib.colors.to_hex(line.get_color())
                       for line in fig.axes[0].legend_.get_lines()]
-            return colors
+            labels = [text.get_text()
+                      for text in fig.axes[0].legend_.get_texts()]
+            return colors, labels
 
         # Default colors should be the default color cycle
         fig = net.cell_response.plot_spikes_raster(trial_idx=0, show=False)
-        colors = _get_line_hex_colors(fig)
+        colors, _ = _get_line_hex_colors(fig)
         default_colors = (plt.rcParams['axes.prop_cycle']
                           .by_key()['color'][0:len(colors)])
         assert colors == default_colors
 
-        # Custom hex colors
+        # Custom hex colors as list
         custom_colors = ['#daf7a6', '#ffc300', '#ff5733', '#c70039']
         fig = net.cell_response.plot_spikes_raster(trial_idx=0, show=False,
                                                    colors=custom_colors)
-        colors = _get_line_hex_colors(fig)
+        colors, _ = _get_line_hex_colors(fig)
         assert colors == custom_colors
 
-        # Custom named colors
+        # Custom named colors as list
         custom_colors = ['skyblue', 'maroon', 'gold', 'hotpink']
         color_map = matplotlib.colors.get_named_colors_mapping()
         fig = net.cell_response.plot_spikes_raster(trial_idx=0, show=False,
                                                    colors=custom_colors)
-        colors = _get_line_hex_colors(fig)
+        colors, _ = _get_line_hex_colors(fig)
         assert colors == [color_map[color].lower() for color in custom_colors]
 
-        # Incorrect number of colors
+        # Incorrect number of colors as list
         too_few = ['r', 'g', 'b']
         too_many = ['r', 'g', 'b', 'y', 'k']
         for colors in [too_few, too_many]:
@@ -336,6 +338,29 @@ def _get_line_hex_colors(fig):
                                                      show=False,
                                                      colors=colors)
 
+        # Colors as dict mapping
+        dict_mapping = {'L2_basket': '#daf7a6', 'L2_pyramidal': '#ffc300',
+                        'L5_basket': '#ff5733', 'L5_pyramidal': '#c70039'}
+        fig = net.cell_response.plot_spikes_raster(trial_idx=0, show=False,
+                                                   colors=dict_mapping)
+        colors, _ = _get_line_hex_colors(fig)
+        assert colors == list(dict_mapping.values())
+
+        # Change color of only one cell type
+        dict_mapping = {'L2_pyramidal': '#daf7a6'}
+        fig = net.cell_response.plot_spikes_raster(trial_idx=0, show=False,
+                                                   colors=dict_mapping)
+        colors, cell_types = _get_line_hex_colors(fig)
+        assert colors[cell_types.index('L2_pyramidal')] == '#daf7a6'
+
+        # Invalid key in dict mapping
+        dict_mapping = {'bad_cell_type': '#daf7a6'}
+        with pytest.raises(ValueError,
+                           match='Invalid cell types provided.'):
+            net.cell_response.plot_spikes_raster(trial_idx=0, show=False,
+                                                 colors=dict_mapping)
+
+
 
 def test_network_plotter_init(setup_net):
     """Test init keywords of NetworkPlotter class."""